import java.util.ArrayList;
import java.util.List;

class Main {
    public List<Integer> findAnagrams(String ss, String pp) {
        List<Integer> ret = new ArrayList<Integer>();
        char[] s = ss.toCharArray();
        char[] p = pp.toCharArray();

        int[] hash1 = new int[26];//统计字符串p中每一个字符出现的个数
        for(char ch : p){
            hash1[ch - 'a']++;
        }

        int[] hash2 = new int[26]; //统计窗口中每一个字符出现的个数
        int m = p.length;

        for(int left = 0,right = 0,count = 0;right < s.length;right++){
            char in = s[right];
            hash2[in - 'a']++;
            if(hash2[in - 'a'] <= hash1[in - 'a']){
                count++;        //进窗口➕维护count
            }
            if(right - left + 1 > m){
                char out = s[left++];
                if(hash2[out - 'a']-- <= hash1[out - 'a']){
                    count--; //出窗口 + 维护 count
                }
            }
            //更新结果
            if(count == m){
                ret.add(left);
            }
        }
        return ret;
    }
}